Knee joint prosthesis system and method for implantation

ABSTRACT

A prosthesis for replacing a knee joint between a femur and a tibia can include a femoral component having a first condylar portion, a second condylar portion, a first sidewall and a second sidewall that collectively comprise a first hinge portion. A tibial component can have a first engagement portion formed thereon. A bearing can have an articulating inferior surface adapted to articulate along the bearing. The bearing can have an opening. A yoke can have an inferior portion and superior portion, the superior portion having an axle that comprises a second hinge portion. The inferior portion can have a second engagement portion and be configured to at least partially pass through the opening. The femoral component is operable to rotate relative to the tibial component about a superior/inferior axis a first rotational distance until the first and second engagement portions engage each other and inhibit further rotation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 11/972,359, filed Jan. 10, 2008, which claims priority to U.S. Provisional Application No. 60/978,949, filed Oct. 10, 2007 and U.S. Provisional Application No. 60/879,733 filed Jan. 10, 2007. The entire disclosures of each of the above applications are incorporated herein by reference.

FIELD

The present disclosure relates to knee joint prosthesis and more particularly to a hinged knee joint prosthesis and a method of assembling and implanting the same.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

A knee joint prosthesis typically comprises a femoral component and a tibial component. The femoral component and tibial component are designed to be surgically attached to the distal end of the femur and the proximal end of the tibia, respectively. The femoral component is further designed to cooperate with the tibial component in simulating the articulating motion of an anatomical knee joint. Such knee joint prostheses are generally referred to as primary knee prostheses.

Knee joint prostheses, in combination with ligaments and muscles, attempt to duplicate natural knee motion as well as absorb and control forces generated during the range of flexion. In some instances however, it may be necessary to replace an existing prosthesis. Such replacement prostheses are generally referred to as revision knee prostheses. In some instances, the primary knee prosthesis, knee tendons and ligaments may become damaged or deteriorated. In this regard, it may be necessary for a revision knee joint prosthesis to eliminate one or more of these motions in order to provide adequate stability. In this way, it may be desirable to provide a cruciate retaining (CR) revision knee, a fully constrained revision knee, a posterior stabilized (PS) revision knee or a hinged revision knee for example. Furthermore, in some instances it may be necessary to account for bone loss in areas adjacent to such knee joint prostheses.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

A prosthesis for replacing a knee joint between a femur and a tibia can include a femoral component having a first condylar portion, a second condylar portion, a first sidewall extending superiorly from the first condylar portion, and a second sidewall extending superiorly from the second condylar portion. The first and second sidewalls can collectively comprise a first hinge portion. A tibial component can have a bone engaging inferior surface and a bearing engaging superior surface. The tibial component can have a first engagement portion formed thereon. A bearing can have an articulating inferior surface adapted to articulate along the bearing engaging surface and a superior femoral engaging surface. The bearing can have an opening. A yoke can have an inferior portion and superior portion, the superior portion having an axle that comprises a second hinge portion that hingedly couples to the first hinge portion. The inferior portion can have a second engagement portion and be configured to at least partially pass through the opening. The femoral component is operable to rotate relative to the tibial component about a superior/inferior axis a first rotational distance until the first and second engagement portions engage each other and inhibit further rotation.

According to additional features, the superior surface of the tibial component has a first bi-helical interface and the inferior surface of the bearing has a second bi-helical interface. The first and second bi-helical interfaces can cooperate to produce a longitudinal distraction of the femoral component relative to the tibial component during the rotation of the femoral component about the superior/inferior axis relative to the tibial component. The first and second hinge portions can cooperate to inhibit distraction of the femoral component relative to the superior surface of the bearing.

According to additional features, the axle can have a hinge axis and further comprise an axle post that is movable along the hinge axis between an installation position and an assembled position. A biasing member can bias the axle post toward the assembled position. In the assembled position, the axle can extend a distance along the hinge axis that is greater than a distance between the first and second sidewalls of the femoral component.

According to still other features, a hyper-extension stop can selectively couple with the yoke and abut an intercondylar portion of the femoral component and inhibit hyper-extension of the femoral component relative to the tibial component. A pin can be selectively advanced through an opening in the hyper-extension stop and engage the axle and thereby inhibit inferior movement of the yoke. The hyper-extension stop can have lateral wings that oppose the first and second sidewalls of the femoral component.

A method of implanting a prosthesis for replacing a knee joint between a femur and a tibia includes implanting a tibial component onto a proximal end of the tibia. The tibial component can have a superior side, including a bearing engaging superior surface, a tibial post and a first engagement portion thereon. An inferior portion of a yoke can be inserted through an opening formed in a bearing. The inferior portion of the yoke can have a bore and a second engagement portion. The yoke and bearing can be rotated in a first rotational direction around an axis of the bore until the first and second engagement portions are at a desired relative orientation. The yoke and bearing can be advanced along the axis of the bore while accepting the tibial post into the bore. The yoke and bearing can be rotated in a second rotational direction, opposite the first rotational direction until the first and second engagement portions are rotationally aligned in an axially opposed position.

According to other features, the first and second engagement portions can have opposing surfaces that are offset a first distance apart. The yoke can be advanced superiorly through the opening of the bearing, thereby positioning the opposing surfaces of the first and second engagement portions a second distance apart, the second distance being less than the first distance.

In other features, the femoral component can be hingedly coupled to a superior portion of the yoke. The coupling can inhibit inferior movement of the yoke through the opening of the bearing. According to one example, the coupling can include depressing a hinge post that is associated with a hinge axle on the yoke until the hinge axle has a first axial length. The hinge axle of the yoke can be advanced between a first and second sidewall of the femoral component. The hinge post can be expanded to a second axial length that is greater than the first axial length, such that the hinge axle operably couples with the femoral component.

According to other features of the present disclosure, a prosthesis adapter for intraoperatively coupling with an implanted tibial tray is provided. The prosthesis adapter can include a hinged bearing adapter having an engaging portion that intraoperatively couples to structure extending superiorly from the tibial tray. The engaging portion can move from an installation position to an assembled position. The hinged bearing adapter intraoperatively converts the tibial tray from a non-hinged profile to a hinged profile that selectively cooperates with a femoral component as a hinged knee prosthesis.

According to additional features, the structure can comprise at least one of a retaining rail that extends from a posterior edge of the tray, a first post that extends from an anterior edge of the tray and a second post that extends from the anterior edge of the tray. In one example, the engaging portion can comprise a first locking bar that advances into engagement with the retaining rail in an assembled position. The engaging portion can further include a second locking bar that advances into engagement with at least one of first and second posts in the assembled position.

According to other features, the engaging portion can comprise a first hinged portion that is hingedly coupled to the hinge bearing adapter. The first hinge portion can rotate from an installation position to an assembled position. In the assembled position, the first hinge portion can at least partially nest within grooves formed in the first and second posts. A fastener can couple the first hinge portion relative to the hinged bearing adapter to maintain the first hinge portion in the assembled position. In other features, the engaging portion can further comprise a second hinge portion that is hingedly coupled to the hinge bearing adapter. The second hinge portion can rotate from an installation position to an assembled position. In the assembled position, the second hinge portion at least partially nests within a channel formed in the retaining rail. A second fastener can couple the second hinge portion relative to the hinged bearing adapter to maintain the second hinge portion in the assembled position.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is an anterior perspective view of a hinged knee joint prosthesis constructed in accordance with one example of the present teachings and shown in an implanted position with a tibia and femur illustrated in phantom;

FIG. 2 is an exploded anterior perspective view of the knee joint prosthesis illustrated in FIG. 1;

FIG. 3 is a medial perspective view of a right femoral component of the hinged knee joint prosthesis of FIG. 1;

FIG. 4 is an anterior view of the femoral component of FIG. 3;

FIG. 5 is an anterior perspective view of a tibial component of the hinged knee joint prosthesis of FIG. 1;

FIG. 6 is a superior view of the tibial component of FIG. 5;

FIG. 7 is a cross-sectional view of the tibial component of FIG. 6 taken along line 7-7;

FIG. 8 is an anterior perspective view of a rotating tibial bearing of the hinged knee joint prosthesis of FIG. 1;

FIG. 9 is a superior view of the rotating tibial bearing of FIG. 8;

FIG. 10 is a superior view of a yoke assembly of the hinged knee joint prosthesis of FIG. 1;

FIG. 11 is a perspective inferior view of the yoke assembly of FIG. 10;

FIG. 12 is an exploded perspective anterior view of the yoke assembly and rotating tibial bearing;

FIG. 13 is a cross-sectional view of the yoke assembly and rotating tibial bearing taken along lines 13-13 of FIG. 12;

FIG. 14 is an exploded anterior perspective view of the tibial component and yoke assembly shown with the rotating tibial bearing in phantom and illustrating the yoke assembly rotated for alignment with the rotating tibial bearing during an assembly step;

FIG. 15 is a superior view of the rotating tibial bearing and yoke assembly shown rotationally aligned with the rotating tibial bearing during assembly, the rotating tibial bearing shown in phantom and the yoke assembly shown in partial phantom;

FIG. 16 is a superior view of the rotating tibial bearing and yoke assembly rotated into an assembled position relative to the tibial component;

FIG. 17 is a cross-sectional view of the assembled yoke assembly, rotating tibial bearing and tibial component taken along lines 17-17 of FIG. 16;

FIG. 18 is a cross-sectional view of the yoke assembly, rotating tibial bearing and tibial component of FIG. 17 shown with the yoke assembly advanced a distance superiorly;

FIG. 19 is an anterior perspective view of the assembled yoke assembly, rotating tibial bearing and tibial component, shown with the rotating tibial bearing in phantom;

FIG. 20 is an anterior perspective view of the yoke assembly and rotating tibial bearing rotating along a bi-helical engagement surface provided between the rotating tibial bearing and the tibial component causing the rotating tibial bearing and yoke assembly to rise superiorly;

FIG. 21 is an anterior view of the bi-helical engagement surfaces of the rotating tibial bearing and tibial component shown with the tibial component in partial section view;

FIG. 22 is an anterior view of the rotating tibial bearing shown rotating with the femoral component about a vertical axis causing the rotating tibial bearing to rise superiorly as a result of slidable engagement between the bi-helical engagement surfaces of the tibial component and rotating tibial bearing;

FIG. 23 is an exploded anterior view of the hinged knee joint prosthesis of FIG. 1 shown with the yoke aligned for receipt into the intercondylar recess of the femoral component;

FIG. 24 is an anterior perspective view of the yoke being received by the intercondylar recess of the femoral component while the femoral component is in flexion and ready for receipt of a hyper-extension stop;

FIG. 25 is a partial anterior perspective view of the yoke assembly assembled with the femoral component and shown with the hyper-extension stop assembled onto the anterior side of the yoke;

FIG. 26 is a partial cross-sectional view of the femoral component, the yoke assembly, the rotating tibial bearing and the tibial component taken along lines 26-26 of FIG. 23;

FIG. 27 is a cross-sectional view of the hinged knee joint prosthesis taken along lines 27-27 of FIG. 1;

FIG. 28 is an anterior view of the rotating tibial bearing and tibial component coupled to an offset stem adapter and stem according to one example of the present teachings;

FIG. 29 is a posterior view of the femoral component shown operatively coupled with a stem adapter and stem according to additional features of the present teachings;

FIG. 30 is an exploded anterior perspective view of a hinged bearing adapter constructed in accordance to one example of the present teachings and shown cooperating with a modular tibial tray;

FIG. 31 is a cross-sectional view of the hinged bearing adapter and tibial tray taken along lines 31-31 of FIG. 30;

FIG. 32 is a cross-sectional view of the hinged bearing adapter and tibial tray of FIG. 31 and shown in an assembled position;

FIG. 33 is a superior view of a hinged bearing adapter constructed in accordance to another example of the present teachings and shown in an assembled position with a modular tibial tray;

FIG. 34 is a cross-sectional view of the hinged bearing adapter and tibial tray taken along lines 34-34 of FIG. 33;

FIG. 35 is an exploded anterior perspective view of another hinged bearing adapter constructed in accordance to additional features of the present teachings and shown with a modular tibial tray 220;

FIG. 36 is a cross-sectional view of the hinged bearing adapter and modular tibial tray taken along line 36-36 of FIG. 35; and

FIG. 37 is a cross-sectional view of the hinged bearing adapter and modular tibial tray of FIG. 36 and shown with a pair of hinged portions locked in an assembled position relative to the modular tibial tray.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

The following description of the embodiments concerning a hinged knee joint prosthesis are merely exemplary in nature and are not intended to limit the disclosure or its application or uses. Moreover, while the present disclosure is described in detail below generally with respect to a hinged knee joint prosthesis, it will be appreciated by those skilled in the art that the present disclosure is clearly not limited to only a hinged knee joint prosthesis and may be applied to various other types of knee joint prostheses. Furthermore, it will be appreciated that the hinged knee joint prosthesis may be used as part of a revision or primary knee joint procedure.

With initial reference to FIGS. 1 and 2, a knee joint prosthesis constructed in accordance to one example of the present teachings is shown and generally identified at reference numeral 10. The knee joint prosthesis 10 is generally shown as a hinged knee joint prosthesis 10, which is designed to provide adequate stability in case of moderate deterioration or instability of the human knee. This most typically occurs when the anterior and posterior cruciate ligaments are sacrificed or dysfunctional. In some examples, the medial and/or lateral collateral ligaments can be functionally in tact or can also be dysfunctional. The knee joint prosthesis 10 illustrated in FIG. 1 is shown secured to a tibia 12 and a femur 14 of a surgically resected left knee joint, with the tibia 12 and the femur 14 shown in phantom, and with the understanding that a suitable right knee joint prosthesis can be similarly constructed. The knee joint prosthesis 10 can generally include a femoral component 16, a tibial component 18, a rotating tibial bearing 20 and a yoke assembly 22.

With continued reference to FIGS. 1 and 2 and additional reference now to FIG. 3, the femoral component 16 will be further described. The femoral component 16 can be adapted to be secured to a distal end of the femur 14 and includes a first condylar portion 26 and a second condylar portion 28 that provide a first femoral bearing surface 30 and a second femoral bearing surface 32, respectively. The first and second condylar portions 26 and 28 of the femoral component 16 can be interconnected by an intercondylar portion 36 that has an intercondylar recess 38. The intercondylar portion 36 can include a first lateral sidewall 40 and a second lateral sidewall 42 that are substantially planar and parallel to one another. Bushings 41 and 43 can be provided on the first and second lateral sidewalls 40 and 42, respectively. The bushings 41 and 43 can be coupled to the first and second lateral sidewalls 40 and 42 or can alternatively be integrally formed with the first and second lateral sidewalls 40 and 42. As will be described herein, the bushings 41 and 43 of the first and second lateral sidewalls 40 and 42 can provide a first hinge portion 44 having a first hinge axis 45. The anterior portions of the first and second lateral sidewalls 40 and 42 can be connected by a superior wall 46. A passage 47 can be formed in the femoral component 16. A superiorly extending portion 48 can be formed on the superior wall 46. The superiorly extending portion 48 can be configured to selectively couple with various adapters and/or stems, such as provided in the Vanguard Complete Knee System (VCKS) manufactured by Biomet Manufacturing Corp. of Warsaw, Ind. A fastener or set screw (not specifically shown) can be advanced through the passage 47 to selectively engage and retain a desired adapter and/or stem. Further description of such components and their assembly to the femoral component may be found in commonly owned and currently pending U.S. patent application Ser. No. 12/248,517, filed on Oct. 9, 2008, which is hereby incorporated by reference.

The femoral component 16 can further include an arcuate patellar portion 50, which is disposed on the anterior surface of the femoral component 16. The patellar portion 50 can be shaped to allow anatomical tracking of a natural or prosthetic patella. The patella prosthesis, which are compatible with the present disclosure may be of varying shape, such as round or dome-shaped and may be constructed from polyethylene, polyethylene with metal backing or other suitable materials. The femoral component 16 can be formed from biocompatible material, such as high strength alloys, including, but not limited to, cobalt-chromium molybdenum alloy or other suitable material. All of the surfaces, which do not contact the femur 14, can be highly polished to provide smooth articulating bearing surfaces.

Turning now to FIGS. 5-7, the tibial component 18 will be further described. The tibial component 18 can be adapted to be secured to the proximal end of the tibia 12 after the tibia 12 has been resected in a manner known in the art. The tibial component 18 can include a platform-like tibial tray 52 having an inferiorly extending tibial stem 54. The tibial stem 54 can be adapted to be received in a corresponding opening made by the surgeon in the longitudinal center of the tibia 12. The tibial tray 52 can have a generally planar inferior bone engaging surface 56 and a bi-helical superior surface 58. The bi-helical superior surface 58 can include a raised middle portion 60, a first depression 64, and a second depression 66, wherein the respective first and second depressions 64 and 66 are formed on either side of the raised middle portion 60.

A superiorly extending post 70 can be centrally formed on the tibial tray 52. An anterior finger 72 and a posterior finger 74 can extend generally superiorly from the raised middle portion 60 of the tibial tray 52. The anterior finger 72 can have a first catch surface 76. The posterior finger 74 can have a second catch surface 78. A channel 80 can be arranged at an annular recess provided between the post 70 and the respective anterior and posterior fingers 72 and 74.

A passage 82 can be formed in the tibial tray 52 that generally extends to the tibial stem 54. The passage 82 can be arranged for accepting a fastener or set screw (not specifically shown) for cooperating with various components (such as stems and/or adapters) that can be coupled to the tibial stem 54. Examples of such stems and adapters may be provided by the Vanguard Complete Knee System (VCKS) manufactured by Biomet Manufacturing Corp. of Warsaw, Ind. Further description of assembly of the tibial component 18 with such components may be found in commonly owned and currently pending U.S. patent application Ser. No. 12/248,517, filed on Oct. 9, 2008, which is hereby incorporated by reference.

The bi-helical superior surface 58 can be substantially polished, such that the rotating tibial bearing 20 may articulate smoothly thereon. The bi-helical superior surface 58 can generally be formed by a first helical portion at the first depression 64 and a second helical portion at the second depression 66. The tibial component 18 can be formed from cobalt-chromium molybdenum or any other suitable biocompatible material. While the anterior finger 72 and the posterior finger 74 are shown and described as being located in an anterior and posterior position on the tibial tray 52, the fingers 72 and 74 can be located at other orientations around the tibial tray 52, such as outboard of the channel 80. In this way, the fingers 72 and 74 can be located at medial and lateral positions or at any angular position relative to the post 70 that can still satisfy the interlocking and functional interconnection with the rotating tibial bearing 20 as will be described.

With reference now to FIGS. 8 and 9, the rotating tibial bearing 20 will be described in greater detail. The rotating tibial bearing 20 can generally include a first bearing portion 90 and a second bearing portion 92. The first and second bearing portions 90 and 92 are configured to substantially mate with and provide an articulating surface to the first and second femoral bearing surfaces 30 and 32 (FIG. 3) of the femoral component 16. Formed between the first and second bearing portions 90 and 92 is an opening 94. The rotating tibial bearing 20 can have a bi-helical inferior surface 96. A first and a second keyway 100 and 102, respectively can be formed on the rotating tibial bearing 20 at the opening 94. In one example, the first and second keyways 100 and 102 can be arranged in a generally opposing manner in an anterior/posterior orientation. An annular relief 104 can be formed on an inferior side of the rotating tibial bearing 20. The annular relief 104 can be formed a distance radially outward relative to the opening 94. As will become appreciated from the following discussion, the annular relief 104 can accommodate the anterior and posterior fingers 72 and 74 of the tibial component 18. The rotating tibial bearing 20 can be formed from a surgical grade, low friction, low wearing plastic, such as ultra high molecular weight polyethylene (UHMWPE) or other suitable material.

With reference now to FIGS. 2, 10 and 11, the yoke assembly 22 will be described in greater detail. The yoke assembly 22 can generally comprise a yoke 110, an axle post 112, a static axle 113, a biasing member 114 and a bushing 116. The yoke 110 can generally comprise a superior portion 120, an inferior portion 122 and an intermediate connecting portion 124. A passage 126 can be formed generally at an intersection of the superior portion 120 and the connecting portion 124. The superior portion 120 can include a blind bore 130 that receives the biasing member 114 and a first end of the axle post 112. The axle post 112 can have an annular channel 132 formed therearound. The axle post 112 and static axle 113 can collectively comprise a second hinge portion 134 having a second hinge axis 135. The inferior portion 122 can have a bore 136 that receives the bushing 116. The inferior portion 122 can have an anterior tang 140 having a superior or upper surface 141 and a posterior tang 142 having a superior or upper surface 143. As will be described, the axle post 112 is biased axially outwardly by the biasing member 114. The yoke 110 can be formed of cobalt-chromium molybdenum or other suitable biocompatible material. The bushing 116 can have an opening 138 and can be formed of non-metallic biocompatible material, such as PEEK. The bushing 116, being formed on non-metallic material can provide a suitable intermediate buffer between an otherwise metal on metal engagement between the post 70 and the bore 136 of the inferior portion 122 of the yoke 110.

With reference now to FIGS. 12-20, one exemplary method for assembling the yoke assembly 22 with respect to the rotating tibial bearing 20 and tibial tray 52 will be described. At the outset, the yoke 110 can be located generally above or superiorly relative to the rotating tibial bearing 20 (FIG. 12). The respective anterior and posterior tangs 140 and 142 provided on the inferior portion 122 of the yoke 110 can then be rotationally aligned with the respective keyways 100 and 102 formed on the opening 94 of the rotating tibial bearing 20 (see FIG. 12). The yoke 110 can then be advanced downward or inferiorly, such that the anterior and posterior tangs 140 and 142 respectively pass through the keyways 100 and 102 until the tangs 140 and 142 reach a position below or inferiorly relative to the respective keyways 100 and 102 (see FIG. 13).

At this point, the rotating tibial bearing 20 and yoke assembly 22 can be collectively located above or superiorly relative to the tibial component 18 as shown in FIG. 13. The post 70 of the tibial component 18 can then be axially aligned with the opening 138 of the bushing 116. With reference to FIGS. 14 and 15, the collective assembly of the rotating tibial bearing and yoke assembly 22 can be rotated about a bushing axis 150 extending longitudinally through the opening 138 of the bushing 116 to a position whereby the anterior and posterior tangs 140 and 142 are rotationally out of alignment with the respective anterior and posterior fingers 72 and 74 of the tibial tray 52. In one example, the yoke 110 can be rotated at an angle 152 that is between 70° and 75° (as best illustrated in FIG. 15). It is appreciated by those skilled in the art, however, that the configuration of the tangs 140 and 142, as well as the fingers 72 and 74 can be arranged differently to require a different angle while still reaching similar results. Once the yoke assembly 22 and the rotating tibial bearing 20 have been collectively rotated a sufficient amount about the bushing axis 150, they can be moved collectively downward or inferiorly, such that the post 70 is received by the opening 138 of the bushing 116.

Turning now to FIGS. 15 and 16, once the anterior and posterior tangs 140 and 142 of the yoke 110 have cleared (passed beyond) the first and second catch surfaces 76 and 78 of the anterior and posterior fingers 72 and 74 of the tibial tray 52, the yoke 110 and bearing tibial bearing 20 may be collectively rotated back to their original position (e.g., to a position where the angle 152 is about 0°) relative to the bushing axis 150 as shown in FIG. 16. In the position shown in FIG. 17, the anterior and posterior tangs 140 and 142 are captured below (inferiorly) the first and second catch surfaces 76 and 78 of the respective anterior and posterior fingers 72 and 74.

With reference now to FIGS. 17 and 18, the yoke 110 can now be advanced (relative to the rotating tibial bearing 20) in a direction superiorly along the bushing axis 150 from a location shown in FIG. 17 to a location shown in FIG. 18. Explained in more detail, the upper surfaces 141 and 143 of the respective tangs 140 and 142 are offset a distance D1 from the respective first and second catch surfaces 76 and 78 as shown in FIG. 17. The yoke 110 can then be advanced superiorly (relative to the rotating tibial bearing 20) to a position as shown in FIG. 18 wherein the upper surfaces 141 and 143 of the respective anterior and posterior tangs 140 and 142 are offset a distance D2 from the first and second respective catch surfaces 76 and 78. As illustrated, D2 is less than D1. It is also important to recognize that D2 is greater than zero.

As shown in FIGS. 19 and 20, when the rotating tibial bearing 20 (and the yoke 110), rotate around the bushing axis 150 (i.e., around an axis extending in the superior/inferior direction) relative to the tibial component 18 from the position shown in FIG. 19 to the position shown in FIG. 20, the respective bi-helical superior surface 58 of the tibial tray 52 and the bi-helical inferior surface 96 of the rotating tibial bearing 20 slidably engage. In this way, the rotating tibial bearing 20 (and the yoke 110) rise superiorly relative to the tibial component 18, such that a distance D3 is now created between the upper surfaces 141 and 143 of the respective anterior and posterior tangs 140 and 142 and the first and second catch surfaces 76 and 78. As shown, D3 is less than D2. In one example as shown in FIG. 20, the respective bi-helical surfaces 58 and 96 can be configured, such that the rotating tibial bearing 20 (and the yoke 110) can rotate to a position, whereby the upper surfaces 141 and 143 of the respective anterior and posterior tangs 140 and 142 engage the first and second catch surfaces 76 and 78 (explained differently, to a position where D3 is zero).

The engagement of the upper surfaces of the tangs 140 and 142 with the first and second catch surfaces 76 and 78 can inhibit subluxation and further rotation of the rotating tibial bearing 20 (and the yoke 110). Once implanted, the only loading the tangs 140 and 142 experience is when they engage the catch surfaces 76 and 78 (i.e., prevention of subluxation). Other loads including varus, valgus, hyper-extension, flexion, and anterior/posterior drawer forces are transferred from the femur 14 through the yoke 110 to the tibia 12 by way of the post 70 of the tibial tray 52.

With reference now to FIGS. 23-26, assembly of the femoral component 16 to the yoke 110 according to one example will now be described. The superior portion 120 of the yoke 110 can be advanced to an area between the first and second lateral sidewalls 40 and 42 of the femoral component 16. The axle post 112 and static axle 113 can then be aligned with the respective first and second bushings 41 and 43. In one example, the axle post 112 can be depressed inward along the second hinge axis 135 (to an installation position shown in phantom line in FIG. 26) against the bias of the biasing member 114 by the surgeon and/or as a result from sliding along the first lateral sidewall 40 of the femoral component 16. Once the axle post 112 and static axle 113 are axially aligned with the first and second bushings 41 and 43, the bias of the biasing member 114 will urge the axle post 112 axially outwardly (to an assembled position shown in solid line in FIG. 26), such that the respective axle post 112 and static axle 113 nest within the respective concave surfaces provided by the first and second bushings 41 and 43 (see FIG. 26). The first and second hinge portions 44 and 134 are now assembled such that the respective first and second hinge axes 45 and 135 are substantially collinear. The femoral component 16 can now rotate about the second hinge axis 135.

Next, a hyper-extension stop 170 can be advanced (posteriorly) to a location that engages the yoke 110 (FIG. 25). The hyper-extension stop 170 can generally comprise lateral wings 174 and 176 and a sloped anterior portion 178. An opening 180 can be formed through the sloped anterior portion 178 of the hyper-extension stop 170. A pin 182 can be separately formed or integrally molded to the opening 180 of the hyper-extension stop 170. During assembly, the pin 182 can be located through the passage 126 formed in the connecting portion 124 of the yoke 110. In one example, the pin 182 can also be located at the annular channel 132 of the axle post 112. In one example, the hyper-extension stop 170 can be advanced into engagement with the yoke 110, while the femoral component 16 (and the femur 14) are in flexion relative to the tibial component 18 (and tibia 12). The hyper-extension stop 170 can engage the intercondylar portion 36 and therefore inhibit a hyper-extension of the tibia 12 relative to the femur 14. Furthermore, engagement to the pin 182 with the axle 112 of the yoke assembly 22 (at channel 132) inhibits inferior movement of the yoke 110. As a result, the anterior and posterior tangs 140 and 142 are precluded from attaining the distance D1 (FIG. 17) from the fingers 72 and 74. Therefore, the anterior and posterior tangs 140 and 142 cannot rotate out of alignment with the fingers 72 and 74 to a position shown in FIG. 15 that could potentially dislocate the yoke 110 from the tibial tray 20. The present configuration of the knee joint prosthesis 10 allows it to be easily applied to a range of tibial tray sizes.

As shown in FIGS. 28 and 29, the tibial component 18 and femoral component 16 can both be configured to selectively couple with various adapters and/or stems such as provided in the Vanguard Complete Knee System described above. For example, an offset adapter 190 and stem 192 are shown cooperatively coupled with the tibial component 18 (FIG. 28) and femoral component (FIG. 29), respectively.

Turning now to FIGS. 30-32, a hinged bearing adapter 218 constructed in accordance to one example of the present teachings will be described. The hinged bearing adapter 218 can be used during a revision procedure to intraoperatively couple with a standard modular tibial base or tray 220. It will be appreciated that the hinged bearing adapter 218 can be formed for intraoperatively connecting with any standard tibial tray for converting a conventional modular tibial tray into a hinged knee joint prosthesis. One exemplary tibial tray is commercially available from Biomet Manufacturing Corp. of Warsaw, Ind. as components of the Maxim® Total Knee System, which includes various sizes and configurations of tibial components for different patient requirements. By converting an existing modular tibial tray (such as 220) into a tibial tray suitable for cooperation with a hinge, removal of the existing modular tibial tray is unnecessary. Therefore, a less invasive procedure can be performed minimizing trauma, bone and tissue loss, etc.

Prior to description of the hinged bearing adapter 218, a brief description of the exemplary tibial tray 220 will now be described. The tibial tray 220 can include a generally flat superior surface 224 having a pair of posts 226 and 228 integrally formed at an anterior edge thereof. A retaining rail 230 can extend superiorly from a posterior edge of the tibial tray 220. The posts 226 and 228 can both have an anterior groove 232 and a posterior groove 234, respectively. The retaining rail 230 can have a transverse groove 240 formed on an inwardly facing surface.

The hinged bearing adapter 218 can generally provide a similar superior profile as described above with respect to the tibial component 18. As can be appreciated, the hinged bearing adapter 218 can cooperate with the components of the hinged knee joint prosthesis 10 as described above. The hinged bearing adapter 218 can have a bi-helical superior surface 244. The bi-helical superior surface 244 can include a raised middle portion 246, a first depression 248, and a second depression 250, wherein the respective first and second depressions 248 and 250 are formed on either side of the raised middle portion 246. A superiorly extending post 252 can be centrally formed on the hinged bearing adapter 218. An anterior finger 254 and a posterior finger 256 can extend generally superiorly from the raised middle portion 246 of the hinged bearing adapter 218. The anterior finger 254 can have a first catch surface 260. The posterior finger 256 can have a second catch surface 262. A channel 264 can be arranged at an annular recess provided between the superiorly extending post 252 and the respective anterior and posterior fingers 254 and 256.

The hinged bearing adapter 218 can have a locking bar 270 slidably received within a bore 272 extending in a posterior direction through the hinged bearing adapter 218. A locking screw 274 can threadably cooperate with the bore 272 during an assembly step as will be described. The hinged bearing adapter 218 can also have a pair of engagement surfaces 276 formed thereon for selectively engaging the posterior grooves 234 on the posts 226 and 228 of the tibial tray 220. A pair of voids 277 can be provided on an anterior portion for accommodating the respective posts 226 and 228 of the tibial tray 220. Similarly, the hinged bearing adapter 218 can have a posterior void 278 configured to receive the retaining rail 230 of the tibial tray 220.

With specific reference now to FIGS. 31 and 32, an exemplary sequence of intraoperatively connecting the hinged bearing adapter 218 to the tibial tray 220 will now be described. Initially, the hinged bearing adapter 218 can be tilted generally anteriorly and advanced toward the flat superior surface 224 of the tibial tray 220. Once the respective engagement surfaces 276 locate at the posterior grooves 234 of the tibial tray 220, the hinged bearing adapter 218 can be rotated generally posteriorly from the position shown in FIG. 31 to the position shown in FIG. 32. The posterior rotation of the hinged bearing adapter 218 can facilitate engagement of the engagement surfaces 276 into an interlocking relationship with the posterior grooves 234 of the respective posts 226 and 228. The locking screw 274 can then be threadably advanced into the bore 272 to advance the locking bar 270 in a direction generally posteriorly and into a nesting position within the transverse groove 240 of the retaining rail 230. The hinged bearing adapter 218 is now securably attached to the tibial tray 220.

With reference now to FIGS. 33 and 34, another hinged bearing adapter 218′ constructed in accordance to additional features of the present teachings will be described. Except as otherwise described, the hinged bearing adapter 218′ can be constructed similarly to the hinged bearing adapter 218 described above with relation to FIGS. 30-32. The hinged bearing adapter 218′ can be used to intraoperatively connect with the tibial tray 220 during a revision knee procedure when it is desired to convert a modular tibial tray (such as the exemplary tibial tray 220 illustrated in the drawings) into a hinged knee joint prosthesis.

The hinged bearing adapter 218′ can have a pair of posteriorly extending bores 280 that each receive a pair of locking bars 282 and 284, respectively. A pair of fasteners 288 can be received in bores 290 that intersect with the respective bores 280. The respective locking bars 282 and 284 can include angled engagement surfaces 292 and 294, respectively. The hinged bearing adapter 218′ can have a pair of void portions 296 arranged on an anterior portion for accommodating the respective posts 226 and 228 of the tibial tray 220. Similarly, the hinged bearing adapter 218′ can have a posterior void portion 298 configured to receive the retaining rail 230 of the tibial tray 220.

During assembly, the hinged bearing adapter 218′ can be advanced inferiorly toward the flat superior surface 224 of the tibial tray 220, such that the posts 226 and 228 are received by the void portions 296 and the retaining rail 230 is received by the posterior void portion 298. The fasteners 288 are then threadably advanced driven into the respective bores 290, such that they slidably advance along the angled surfaces 292 and 294 of the respective locking bars 282 and 284. This action causes the locking bars 282 to advance posteriorly into engagement with the transverse groove 240 of the retaining rail 230. This action also causes concurrent movement of the locking bars 284 to advance anteriorly into engagement with the posterior grooves 234 of the posts 226 and 228.

With reference now to FIGS. 35-37, another hinged bearing adapter 218″ constructed in accordance to additional features of the present teachings will be described. Except as otherwise described, the hinged bearing adapter 218″ can be constructed similarly to the hinged bearing adapter 218 described above with relation to FIGS. 30-32. The hinged bearing adapter 218″ can be used to intraoperatively connect with the tibial tray 220 during a revision knee procedure when it is desired to convert a modular tibial tray (such as the exemplary tibial tray 220 illustrated in the drawings) into a hinged knee joint prosthesis.

The hinged bearing adapter 218″ can include first and second hinge portions 302 and 304. The hinge portions 302 and 304 can rotate about respective axles 306 and 308, respectively. A pair of passages 312 and 314 can be formed through the hinged bearing adapter 218″ for receipt of the respective axles 306 and 308 during a manufacturing step.

The first hinge portion 302 can include a pair of notch portions 320 and 322 for cooperating with the respective posts 226 and 228 during intraoperative assembly of the hinged bearing adapter 218″ to the tibial tray 220. First and second throughbores 326 can be formed through the first hinge portion 302. Similarly, a throughbore 328 can be formed through the second hinge portion 304. A complementary pair of passages 330 can be formed through the hinged bearing adapter 218″ that align coaxially with the throughbores 326 in an installed position as will be described. Similarly, an opening 332 can be formed through the hinged bearing adapter 218″ for aligning coaxially with the throughbore 328 of the second hinge portion 304 in an assembled position as will be described. Set screws 336 can be provided for aligning with the respective passages 330 and 332 and the throughbores 326 and 328.

During an exemplary assembly sequence, the hinged bearing adapter 218″ can be advanced inferiorly toward the flat superior surface 224 of the tibial tray 220, such that the first hinge portion 302 locates into an interlocked position with the anterior grooves 234 of the first and second posts 226 and 228, respectively. Similarly, the second hinge portion 304 can locate into the transverse groove 240 of the retaining rail 230. As the hinged bearing adapter 218″ is further advanced inferiorly, the first hinge portion 302 rotates about the hinge axle 306 in a counterclockwise direction (as viewed in FIG. 36) while the second hinge portion 304 rotates about the hinge axle 308 in a clockwise direction until reaching a generally horizontal position relative to the flat superior surface 224 of the tibial tray 220 as shown in FIG. 37.

The set screws 336 can then be threadably advanced through the respective passages 330 and 332 to threadably mate with the throughbores 326 and 328 to effectively lock the first and second hinge portions 302 and 304 in a closed position and locked relative to the tibial tray 220. It is appreciated that the first and second hinge portions 302 and 304 can be constructed differently. Likewise, it is appreciated that the interlocking feature may be achieved with only a single hinge or alternatively additional hinge portions. Likewise, the location and configuration of the respective passages 330 and 332 is merely exemplary and other locations may be additionally or alternatively provided. Moreover, other configurations may be implemented for selectively locking the respective first and second hinge portions 302 and 304 in the locked position shown in FIG. 37.

As used herein, the terms superior, superiorly, superior direction are used to generally refer to the anatomical meaning, such as higher in place or position or generally situated above. Similarly, the terms inferior, inferiorly, inferior direction are used to generally refer to the anatomical meaning, such as lower in place or position or generally situated below.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

1. A prosthesis for replacing a knee joint between a femur and a tibia, the prosthesis comprising: a femoral component including a first condylar portion, a second condylar portion, a first sidewall extending superiorly from the first condylar portion, a second sidewall extending superiorly from the second condylar portion, the first and second sidewalls collectively comprising a first hinge portion; a tibial component having a bone engaging inferior surface and a bearing engaging superior surface; a bearing having an articulating inferior surface adapted to articulate along the bearing engaging surface and a superior femoral engaging surface, the bearing having a keyway that defines an opening; and a yoke having an inferior portion and a superior portion, the superior portion comprising a second hinge portion that hingedly couples to the first hinge portion, the second hinge portion including an axle defining a hinge axis and having an axle post that is movable along the hinge axis between an installation position and an assembled position, the inferior portion configured to at least partially pass through the opening; wherein the tibial component has a first engagement portion formed thereon including at least one superiorly extending finger having a catch surface that generally opposes the bearing engaging superior surface and wherein the inferior portion of the yoke has a second engagement portion formed thereon including at least one tang having a superior surface that generally opposes the catch surface, wherein the keyway accommodates the at least one tang upon passage of the yoke through the opening of the bearing.
 2. The prosthesis of claim 1 wherein the femoral component comprises a bushing on each of the first and second sidewalls, respectively that receive at least portions of the axle in a nested position in the assembled position.
 3. The prosthesis of claim 2, further comprising a biasing member that biases the axle post toward the assembled position.
 4. The prosthesis of claim 2 wherein in the assembled position the axle extends a distance along the hinge axis that is greater than a distance between the first and second sidewalls of the femoral component.
 5. The prosthesis of claim 1, further comprising a hyper-extension stop that selectively couples with the yoke and abuts an intercondylar portion of the femoral component and inhibits hyper-extension of the femoral component relative to the tibial component.
 6. The prosthesis of claim 5, further comprising a pin that selectively advances through an opening in the hyper-extension stop and engages the axle and thereby inhibits inferior movement of the yoke.
 7. The prosthesis of claim 6 wherein the hyper-extension stop has lateral wings that oppose the first and second sidewalls of the femoral component.
 8. The prosthesis of claim 1 wherein the superior surface of the tibial component has a first bi-helical interface and the inferior surface of the bearing has a second bi-helical interface, the first and second bi-helical interfaces cooperating to produce a longitudinal distraction of the femoral component relative to the tibial component during the rotation of the femoral component about the superior/inferior axis relative to the tibial component.
 9. The prosthesis of claim 8 wherein the longitudinal distraction is inhibited upon sufficient rotation of the femoral component about the superior/inferior surface such that the catch surface of the finger and the superior surface of the tang abut.
 10. The prosthesis of claim 1 wherein the inferior portion of the yoke has a boss that receives a post extending from the bearing engaging surface of the tibial component.
 11. The prosthesis of claim 10 further comprising a bushing interposed between the post and the boss of the yoke, the bushing formed of a non-metallic material.
 12. The prosthesis of claim 10 wherein the tibial component has an annular channel into the bearing engaging surface between the post and the at least one finger, the annular channel accommodating the at least one tang of the yoke.
 13. A prosthesis for replacing a knee joint between a femur and a tibia, the prosthesis comprising: a femoral component including a first condylar portion, a second condylar portion, a first sidewall extending superiorly from the first condylar portion, a second sidewall extending superiorly from the second condylar portion, the first and second sidewalls collectively comprising a first hinge portion; a tibial component having a bone engaging inferior surface and a bearing engaging superior surface, the tibial component having a first engagement portion formed thereon including a superiorly extending finger, wherein the superior surface of the tibial component has a first bi-helical interface and the inferior surface of the bearing has a second bi-helical interface, the first and second bi-helical interfaces cooperating to produce a longitudinal distraction of the femoral component relative to the tibial component during the rotation of the femoral component about the superior/inferior axis relative to the tibial component; a bearing having an inferior surface that engages the bearing engaging surface and a superior femoral engaging surface, the bearing having a keyway that defines an opening; and a yoke having an inferior portion and a superior portion, the superior portion having an axle that comprises a second hinge portion that hingedly couples to the first hinge portion, the inferior portion having a second engagement portion including a tang, the second engagement portion configured to at least partially pass through the opening to a position wherein the tang generally opposes a portion of the finger, wherein the keyway accommodates the tang upon passage of the yoke through the opening of the bearing.
 14. The prosthesis of claim 13 wherein the first and second hinge portions cooperate to inhibit distraction of the femoral component relative to the superior surface of the bearing.
 15. The prosthesis of claim 13 wherein the axle has a hinge axis and further comprises an axle post that is movable along the hinge axis between an installation position and an assembled position.
 16. The prosthesis of claim 15, further comprising a biasing member that biases the axle post toward the assembled position.
 17. The prosthesis of claim 15 wherein in the assembled position the axle extends a distance along the hinge axis that is greater than a distance between the first and second sidewalls of the femoral component.
 18. The prosthesis of claim 13, further comprising a hyper-extension stop that selectively couples with the yoke and abuts an intercondylar portion of the femoral component and inhibits hyper-extension of the femoral component relative to the tibial component.
 19. The prosthesis of claim 18, further comprising a pin that selectively advances through an opening in the hyper-extension stop and engages the axle and thereby inhibits inferior movement of the yoke.
 20. The prosthesis of claim 19 wherein the hyper-extension stop has lateral wings that oppose the first and second sidewalls of the femoral component.
 21. A prosthesis for replacing a knee joint between a femur and a tibia, the prosthesis comprising: a femoral component including a first condylar portion, a second condylar portion, a first sidewall extending superiorly from the first condylar portion, a second sidewall extending superiorly from the second condylar portion, the first and second sidewalls collectively comprising a first hinge portion; a tibial component having a bone engaging inferior surface, a bearing engaging superior surface and an engagement portion including at least one superiorly extending finger; a bearing having an articulating inferior surface adapted to articulate along the bearing engaging surface and a superior femoral engaging surface, the bearing defining an opening; and a yoke having an inferior portion and a superior portion, the superior portion comprising a second hinge portion that hingedly couples to the first hinge portion, the second hinge portion including an axle defining a hinge axis and having an axle post that is movable along the hinge axis between an installation position and an assembled position, the inferior portion configured to at least partially pass through the opening, wherein the inferior portion of the yoke has a second engagement portion including at least one tang, the yoke further including a boss that receives a post extending from the bearing engaging surface of the tibial component and wherein the tibial component has an annular channel into the bearing engaging surface between the post and the at least one finger, the annular channel accommodating the at least one tang of the yoke.
 22. The prosthesis of claim 21 wherein the superior surface of the tibial component has a first bi-helical interface and the inferior surface of the bearing has a second bi-helical interface, the first and second bi-helical interfaces cooperating to produce a longitudinal distraction of the femoral component relative to the tibial component during the rotation of the femoral component about the superior/inferior axis relative to the tibial component. 